Answer:
12 inches
Step-by-step explanation:
let length be L
formula for perimeter of rectangle = 2( length + width )
2( L + 9) = 42
2L + 18 = 42
2L = 24
L = 12 inches
F(x) = 3x+1
G(x) = X^2 - 6
F(G(x)) = F(X^2 - 6) = 3(X^2 - 6) + 1 = 3X^2 - 18 + 1 = 3X^2 -17
F(G(x)) = 3X^2 - 17
F(x) is y so, y = 6x - 3.
Flip the equation around to get x= 1/6y + 1/2
Equation of the line:
y = -4x + 1